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Debian LinuxOperating system · Debian

CVE-2017-7826

CRITICAL · 9.8 CVSS v3.0 Published 2018-06-11
Fix available
A fix is available. Upgrade to 52.5.0 / 57.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Memory safety bugs were reported in Firefox 56 and Firefox ESR 52.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 57, Firefox ESR < 52.5, and Thunderbird < 52.5.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Memory safety vulnerabilities in Firefox and Thunderbird allowed memory corruption that could potentially be exploited to execute arbitrary code. The bugs were present in the browser engine and related to improper memory handling in Firefox 56 and Firefox ESR 52.4.

MitigationUpgrade immediately to Firefox 57+, Firefox ESR 52.5+, or Thunderbird 52.5+ to patch the memory corruption vulnerabilities. Given the CVSS 9.8 severity and potential for arbitrary code execution, this should be prioritized as an urgent patch.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 7.0= 8.0= 9.0
Enterprise Linux DesktopOperating system
Affected:= 6.0= 7.0
Enterprise Linux ServerOperating system
Affected:= 6.0= 7.0
Enterprise Linux Server AusOperating system
Affected:= 7.4
Enterprise Linux Server EusOperating system
Affected:= 7.4= 7.5
Enterprise Linux WorkstationOperating system
Affected:= 6.0= 7.0
Ubuntu LinuxOperating system
Affected:= 17.10= 18.04
FirefoxWeb browser
Affected:< 57.0< 52.5.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if Mozilla Firefox is installed
    On Windows, check Program Files or Program Files (x86) for Mozilla Firefox folder. On Linux, run 'which firefox' or check /usr/bin/firefox. On macOS, check /Applications for Firefox.app
    Affected if Firefox is installed and running a version below 57.0 or below 52.5.0 for ESR releases
  2. Determine installed Firefox version
    On Windows, open Firefox, click menu > Help > About Firefox. On Linux terminal, run 'firefox --version' or check the package with 'rpm -q firefox' (RHEL) or 'dpkg -l firefox' (Debian/Ubuntu). On macOS, right-click Firefox.app > Get Info
    Affected if The displayed version number is less than 57.0 for standard releases or less than 52.5.0 for ESR releases
  3. Check if Thunderbird is installed
    On Windows, check Program Files for Mozilla Thunderbird. On Linux, run 'which thunderbird' or check /usr/bin/thunderbird. On macOS, check /Applications for Thunderbird.app
    Affected if Thunderbird is installed and runs a version that shares the vulnerable engine code (implied affected based on CVE summary mentioning Thunderbird)
  4. Verify distribution package versions on Linux
    For RHEL/CentOS: 'rpm -qa | grep -i firefox'. For Debian/Ubuntu: 'dpkg -l | grep -i firefox'. Compare output to known affected versions: Debian 7.x/8.x/9.x, RHEL 6.x/7.x, Ubuntu 17.10/18.04
    Affected if The installed package version corresponds to the listed affected Debian, RHEL, or Ubuntu versions that ship vulnerable Firefox versions

A user is affected if they run Firefox version below 57.0 (or below 52.5.0 for ESR) or Thunderbird sharing the same vulnerable engine, particularly on the listed Linux distributions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 52.5.0 / 57.0 or later
Fixed in 52.5.057.0
Interim mitigation

Upgrade immediately to Firefox 57+, Firefox ESR 52.5+, or Thunderbird 52.5+ to patch the memory corruption vulnerabilities. Given the CVSS 9.8 severity and potential for arbitrary code execution, this should be prioritized as an urgent patch.

Recommended fix High confidence

Firefox 57.0 or later / Firefox ESR 52.5.0 or later

  1. Back up bookmarks, passwords, and any essential browser data before upgrading
  2. Update Firefox to version 57.0 or later (or Firefox ESR 52.5.0 or later for enterprise deployments)
  3. Restart the browser to complete the update
  4. Verify the update by checking Help > About Firefox to confirm the version number
Caveat Firefox 57 introduced significant extension API changes (WebExtensions); some legacy add-ons may not be compatible

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $910
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,456.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-7826 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data